Gorczyca M G, Hall J C
J Neurosci. 1987 May;7(5):1361-9. doi: 10.1523/JNEUROSCI.07-05-01361.1987.
The distribution of choline acetyltransferase (CAT) in the nervous system of Drosophila melanogaster was determined by indirect immunohistochemical procedures using a monoclonal antibody specific to the enzyme. Immunoreactivity was first detected in the nervous system of 16 hr embryos, and increased considerably by the end of embryogenesis. Neuropil was preferentially stained, though cell bodies could also be observed. Staining was prominent in the CNS of all 3 larval instars but decreased substantially during the mid-pupal stage. Prior to eclosion, the level of immunoreactivity increased and the adult staining pattern became discernible. In the adult brain, staining was extensive, with numerous structures, such as the optic lobes and mushroom bodies, staining strongly. The adult thoracic ganglia were also moderately immunoreactive. These results imply a wide distribution of cholinergic neurons in the CNS of Drosophila. Immunoreactivity was also determined for 2 temperature-sensitive CAT mutants, Chats1 and Chats2. These files exhibit reduced CAT activity at permissive temperature, 18 degrees C, which eventually falls to undetectable levels after incubation at nonpermissive temperature, 30 degrees C. Chats2 mutants, after incubation at either 18 or 30 degrees C displayed virtually no staining. This result indicated that the immunoreactivity observed in wild-type flies was specifically associated with the enzyme encoded by the Cha gene. The intensity of staining in Chats1 mutants incubated at 18 degrees C appeared greater than in control flies, even though CAT enzyme activity in Chats1 is lower. This suggests that the enzyme molecule itself is structurally altered in Chats1 mutants. After incubation at 30 degrees C, staining in Chats1 flies decreased but did not disappear.
利用针对胆碱乙酰转移酶（CAT）的单克隆抗体，通过间接免疫组织化学方法确定了果蝇神经系统中该酶的分布。在16小时胚胎的神经系统中首次检测到免疫反应性，到胚胎发育结束时显著增加。神经纤维网优先被染色，不过也能观察到细胞体。在所有3个幼虫龄期的中枢神经系统中染色都很明显，但在蛹中期显著减少。羽化前，免疫反应性水平升高，成虫的染色模式变得清晰可辨。在成虫大脑中，染色广泛，许多结构，如视叶和蘑菇体，染色强烈。成虫胸神经节也有中度免疫反应性。这些结果表明胆碱能神经元在果蝇中枢神经系统中广泛分布。还对2个温度敏感的CAT突变体Chats1和Chats2进行了免疫反应性测定。这些果蝇在允许温度18℃时CAT活性降低，在非允许温度30℃孵育后最终降至无法检测的水平。Chats2突变体在18℃或30℃孵育后几乎没有染色。这一结果表明在野生型果蝇中观察到的免疫反应性与Cha基因编码的酶特异性相关。在18℃孵育的Chats1突变体中的染色强度似乎比对照果蝇中的更大，尽管Chats1中的CAT酶活性较低。这表明Chats1突变体中的酶分子本身在结构上发生了改变。在30℃孵育后，Chats1果蝇中的染色减少但没有消失。
